The core for this program project is divided into two parts. Part A is HLA typing of all the diabetic patients to be studied in this research proposal--primarily at the Barbara Davis Diabetes Center at the University of Colorado, the Endocrinology Clinic at the University of Washington, and the Pediatric Endocrinology Clinic at the Medical of Wisconsin. In addition, a small number of patients will be studied at Stanford University, coming from the Pediatric Endocrinology Clinic of the Lucille Salter Children's Hospital. In this core, Dr. Henry Erlich will use polymerase chain reaction (PCR) based methods to type the HLA DR B1 and DQ B1 genotype of the patients to be studied in this study. Since these three major and one minor diabetes clinic between 250 to 300 new diabetes patients per year, the numbers of patients to be typed will approach that number, although it is not likely that all patients will be studied since those of very young age will not be able to donate sufficient amounts of peripheral blood for the studies required. Part B of the core is to provide for travel costs and housing costs for two investigators from each of the participating institutions to travel to a central site (e.g. Seattle, Denver, or Palo Alto) for presentation and comparison of results, modifications of experimental protocols, and decisions as to which aspects of each study need to be repeated, extended, or if necessary, discontinued.